Due to the dramatic development of Internet technologies, social networking services (SNS) which provide a variety of services by establishing and using a network among users via the Internet recently have been popular.
In particular, one of the most essential functions of the SNS is to introduce many other users to a specific user and gives the specific user a chance to widen his or her social network (so called, a function of recommending friends). One of the existing technologies, which are introduced many times, as such a friend recommendation technology was a technology for analyzing the information on objects which users have their interest in and recommending other users with similar preference to a specific user. For example, if user A usually visits Starbucks and Coffee Bean among various coffee shops and user B mainly visits Tom N Toms and Passcucci while user C loves Starbucks and Caffebene, the technology is to recommend the user C who is considered to have more similar preference with the user A.
In case of the existing technology which simply used correspondence relationships between users and objects, because the types of objects are too voluminous, one same specific object was not very frequently selected. Therefore, it was really difficult to find users with similar preference with the user A. In short, in the aforementioned example, if there is no coffee shop in which the users A, B and C are jointly interested, even though all the users like coffee, the users were classified as users with dissimilar preference. If it is assumed that there are various types of products beyond coffee shops having relatively fewer types, users might face the problem more seriously.
Accordingly, the applicant of the present invention came to develop a technology for introducing a concept of topic which is a more comprehensive concept than a concept of object to thereby evaluate degrees of similarity between each user more widely and supporting the recommendation of a specific object with a high degree of relationship with a specific user to other users who have similar preference with the specific user.